Around 3,000 people are left in eastern Aleppo, said Syrian activists on Tuesday, and are waiting to be evacuated before the government resumes its full control of the city.

Opposition media activist Ahmad Primo said that the next convoy of buses that's going to take rebels and civilians out may well be the last one. Primo spoke to The Associated Press from the Rashideen crossing between government and rebel-held territory in the Aleppo countryside.

Around 60 buses have entered to pick up the remaining 3,000 fighters and their families, said Britain-based Syrian Observatory for Human Rights.

Russian Foreign Minister Sergey Lavrov said on Tuesday that Russia, Iran and Turkey are ready to act as guarantors in a peace deal between the Syrian government and the opposition.

Lavrov told reporters the three ministers have signed a joint statement which says that Russia, Iran and Turkey "are expressing their willingness to help the Syrian government and the opposition draft an agreement and act as its guarantors,” according to The Associated Press.

Observatory's chief Rami Abdurrahman said the fate of 70 pro-government fighters taken prisoner by rebels over the course of four years of fighting over the rebel enclave remains unknown. He also said they were supposed to be handed over to the government as part of an agreement to allow the opposition to evacuate the city.